UPDATES FROM gear-devel sql:

ALTER TABLE dataset:
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ALTER TABLE dataset ADD COLUMN share_id VARCHAR(50) NOT NULL AFTER schematic_image;


ADD dataset_shares table:
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CREATE TABLE dataset_shares(id INT PRIMARY KEY AUTO_INCREMENT, dataset_id VARCHAR(50) NOT NULL, user_id INT NOT NULL, is_allowed TINYINT(1) DEFAULT 0, FOREIGN KEY (dataset_id) REFERENCES dataset(id) ON DELETE CASCADE, FOREIGN KEY (user_id) REFERENCES guser(id) ON DELETE CASCADE) ENGINE=INNODB;